For the associated Legendre function of the first kind we have [1]}:
\(P^{\lambda -a-1/2}_{n+a-1/2}(0)=\dfrac{2^{\lambda -a-1/2}\sqrt{\pi }}{\Gamma \left(\dfrac{n+2a-\lambda +2}{2}\right)\Gamma \left(\dfrac{2-\lambda -n}{2}\right)}.\) 
